So that's why i haven't been able to reach the add-on server lately.
Only problem: i registered on the forums but i still don't know how to reach the add-on server - it keeps disconnecting every time i try. Where am i supposed to enter my account name & password?

Please use proper spelling and grammar. There are a number of reasons why you might not be able to join a game (a host can make a game password protected, or enable plugins that everyone must have, etc). What exactly were you trying to do and what error message did you get?